Effects of immobilization stress on regional cerebral blood flow in the conscious rat.
Immobilization stress of conscious, normotensive, freely breathing 10-month-old Wistar-Kyoto rats produced an overall decline in regional cerebral blood flow (rCBF), as measured with [14C]iodoantipyrine, except at the frontal lobe. In 14 brain regions, rCBF fell by an average of 14.3% after 5 min of immobilization and by 11.9% after 15 min. Immobilization stress also stimulated hyperventilation and thereby reduced PaCO2. The slope relating rCBF to PaCO2 averaged 1.5 ml 100 g-1 min-1 mm Hg-1 in 9 significantly affected regions. The findings suggest that rCBF declines during immobilization stress because of cerebrovascular constriction caused by a reduction in PaCO2. Comparison of the average slope with published values in indicates furthermore that were PaCO2 to remain unchanged during immobilization, rCBF would increase by at most 20%.
D000136:Acid-Base Equilibrium; D000818:Animals; D001158:Arteries; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood; D002560:Cerebrovascular Circulation; D006339:Heart Rate; D006863:Hydrogen-Ion Concentration; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000503:physiopathology*
D002245:Carbon Dioxide